Apparatus for texturing the surface of a brake plate

ABSTRACT

A method for texturizing a workpiece uses a die assembly installed within a press having a press ram. The method includes (a) delivering the workpiece onto a centre die plate; (b) forcing the press ram against an upper die plate mounted above the centre die plate to descend a first contact surface associated with the upper die plate and a plurality of blades mounted to the upper die plate toward the centre die plate; (c) actuating horizontal movement of the blades; (d) driving the blades down into the workpiece; and (e) contacting the first contact surface to a second contact surface associated with the centre die plate to descend the centre die plate in unison with the upper die plate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/333,290 filed Oct. 25, 2016, which is a divisional of U.S. patentapplication Ser. No. 14/877,375 filed Oct. 7, 2015, which is acontinuation of U.S. patent application Ser. No. 13/706,120 filed Dec.5, 2012 (now U.S. Pat. No. 9,199,322, issued on Dec. 1, 2015), whichclaims priority from Canadian Patent Application No. 2,760,923, filedDec. 6, 2011 (now CA Pat. No. 2,760,923, issued Mar. 11, 2014), each ofwhich is incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to apparatuses for texturing the surface of abrake plate.

Description of the Related Art

Secure brakes being all-important, the use of textured plates to anchorthe friction pad is extremely desirable. However, the additional cost ofplate texturing limits their real-world use to severe-service andhigh-end vehicles where the added cost is irrelevant. It would bedesirable to lower the cost of texturing brake plates so that morewidespread use could be made of this safety feature.

SUMMARY OF THE INVENTION

An apparatus is provided for texturing the surface of a brake platehaving three die plates and spring supports therebetween. A toothedtooling mounts to the top die plate above an anvil on the centre dieplate both of which ride on posts held by the lower die plate. Thetoothed tooling comprises multiple blades each with multiple replaceabletoothed inserts which are held in a cartridge arrangement. The anvilreceives brake plates from a separately supported plate feed mechanism.The complete die set can be set up on the bench and inserted ready touse in any style of press where the press ram contacts the upper dieplate.

The three die plates of the present invention are all aligned onvertical posts. The posts are secured to the bottom or base die platesuch that the centre and upper die plates are free to reciprocatethereon with the upper die plate uniquely carrying the texturizingtooling. In this way the entire die set installs as a free-standingone-piece assembly. The die set is mountable in a mechanical, hydraulicor servo type press.

This contrasts with prior apparatuses of this type in which texturizingtooling was attached to the press ram. This required that the lower,two-plate die set had to be precisely located beneath—a difficult taskgiven the mass of the die set.

Certain support and actuation members are secured to the base die plate.Certain anvil structures are secured to the centre die plate. Certaincutting and press contact structures are secured to the upper die plate.

Accordingly, an apparatus is provided for texturing the surface of abrake plate. The apparatus comprises an independent and free-standingdie set for use within a press. The die set has: a base die plate; acentre die plate; and an upper die plate. The base die plate isattachable to the press and has a series of fixed posts extending upwardtherefrom. The centre die plate is mounted above the base die plate onthe posts and is also movable thereon. The centre die plate has an anvilportion for receiving a brake plate to be textured. The upper die plateis mounted above the centre die plate on the posts and is also movablethereon. The upper die plate has a tooling assembly with a plurality ofoppositely acting blades located above the anvil portion. Opposing camblocks are mounted below the upper die plate adjacent the oppositelyacting blades. All of the plates are arranged in series such thatdownward force from the press urges the upper die plate into contactwith the centre die plate, and the centre die plate downward toward thebase die plate, and thereby actuates the cam blocks to drive teeth ofthe oppositely acting blades across and into the surface of the brakeplate on the anvil. This action textures the surface of the brake plate.The base die plate is the only portion of the die set that attaches tothe press.

For example, the base die plate may be built on a thick steel plate thatbolts to the bolster of the press machine. Preferably, the plates arespring-biased apart. Four permanent vertical posts and four removablegas springs are arranged on the base. The springs may be manifoldedtogether to equalize their spring rate and gas delivery so as to providebalanced support for the center die plate. By altering the gas pressure,the gas spring force can be adjusted for different sizes (surface areasor thicknesses) of brake plates to be textured (by providing more orless cutter action).

In one embodiment, the base die plate further includes opposing riserblocks, and the centre plate further includes opposing openings directlyabove the riser blocks. The riser blocks then extend through theopenings to contact portions of the cam blocks to actuate the cam blocksas the upper and centre die plates descend. Preferably, each cam blockhas a vertical motion member and a horizontal blade moving member. Thevertical motion member receives counterforce from the riser blocks, andengages into motion the horizontal blade moving member. The moving camsmove the blades to carry out the texturing. (It will be appreciated thatother methods of linear actuation of the blades are also possible.)

According to one embodiment, in operation, the press ram descends ontothe upper die plate. The upper die plate then descends, engaging the twocams simultaneously. This initiates blade travel slightly prior to thecutting teeth inscribing the plate to create the required hooked burrs.In this way the cutting teeth are in horizontal motion before they drivedown into the plate. The ram then ascends and the above the sequence ofactions are reversed. The now textured plate is pushed off the anvil bya new incoming plate and the process repeats itself.

Smooth operation of the die set is desirable. The upper die plate mayreciprocate on the posts via bushings. Its upper surface is contacted bythe press ram. Preferably, the upper die plate has at least oneelastomeric shock absorber disposed on an upper surface thereof.Multiple (preferably urethane) shock absorbing pads may be disposed onthe top surface of the upper die plate. These pads are held incounterbored recesses such that the descending press ram contacts thesepads first, thus providing a smooth and silent initiation of downwardmotion of the upper die against the initial resistance offered by thesmall gas springs.

The apparatus may further include a plate feed mechanism engageable withthe centre plate. The plate feed mechanism has a magazine for holdingbrake plates to be textured; and a reciprocating slide mechanism forpushing brake plates onto the anvil one by one as they descend from themagazine. Preferably, the load of the magazine is supportedindependently of the die set. Preferably, the plate feed mechanism isdetachable from the die set. Preferably, the plate feed mechanismfurther includes a pawl for preventing rearward motion of the brakeplate. Preferably, the reciprocating slide mechanism has a variabledelivery angle.

The weight of the plate feed mechanism is preferably supported on asolid mounting block secured to the base die plate (or press bolster).This greatly reduces the reciprocating mass on the die set allowing ahigher rate of reciprocation for faster plate texturizing and reducedcost. Reduced reciprocating mass also eliminates expensive wear fromside thrust on the die set posts and bushings which would otherwiseoccur if the entire plate feed mechanism were cantilevered from- andmade to reciprocate with the die plate, as is the case in the prior art.Such wear necessitates the tear down of the entire die set to replacethe worn posts and bushings. The result is a long non-productivedown-time to rebuild the dies and the attendant labour expense.

The plate feed apparatus comprises a plate magazine assembly, a platefeed slide assembly, and a pneumatic linear actuator for the slide, allsupported by the solid mounting block on the base die. The plate slideassembly uses long steel strips as slides in a laminated assembly whichare separate from, but pass through and are guided by, the magazineassembly. The slides connect to a hinge block at their outboard (distal)end. This hinge block is separately supported on rods extending fromthat same solid mounting block (on base die plate die) along which rodsit can reciprocate along with the plate slides. These rods also supportthe stationary actuating cylinder (pneumatic) which reciprocates thehinge block and slides. The inner (proximal) end of the lower plateslide rests on rollers secured to the edge of the centre die. The upperslide plate has features to receive a plate from the stack of platesheld in the magazine above. Thus when the cylinder is activated, thereciprocating slides pick up plates on each rearward stroke and deliverthe plates in a train-like flow to the anvil for texturing.Spring-loaded pawls or detents prevent the plates from moving backwardswith the slide. In this way only a very small portion of the totalweight of the plate feed mechanism is reciprocating with the centre die.Thus the posts and bushings do not experience the heavy wear known to bea serious problem with prior methods of plate delivery.

Various blade arrangements are possible. Preferably, the blades areopposingly arranged in the tooling assembly, such that adjacent bladeshave teeth oriented in opposed directions. The blades may be solidcutting knives, or may include modular inserts. Each blade preferablyhas at least one cut-out for receiving at least one insert. The inserthas a first end on which is disposed a plurality of cutting teeth and asecond end having a bulbous projection shaped to loosely engage acorrespondingly shaped recess in the at least one cut-out. Preferably,the insert when inserted into the cut-out leaves a gap below the bulbousportion. Preferably, the insert is shaped to wedgingly engage the recessto narrow the gap under force of operation in the press.

Preferably, the inserts and cut-outs have corresponding side taperportions for seating and bulbous bottom portions for retention. Thebulbous portion of the cut-out is slightly deeper that of the insert.Thus, there is a gap between the bottom surface of the insert and thebottom surface of the cut-out. In operation the incising force acting onthe cutting edge is able to drive the insert a small distance into thetapered cut-out such that the insert wedges very tightly, effectivelyimmobilizing the insert in the blade. Because carbide is very friableand fractures easily if allowed to shudder or vibrate under the highcutting forces required to incise steel, this rigidity greatly prolongsthe life of the teeth which reduces costs and reduces press down-timefor tooling change-out.

The blade cartridge comprises the cutter blades (with the aforementionedtoothed inserts) slidingly held in precisely aligned rows between robustside supports that are secured to a common backing plate which hasmounting rails to slidingy engage grooves in a plate attached to the topdie. The blades and the side supports all have open slots at each endthat are in alignment and through which slots are pins that extendoutboard of each side support to provide attachment for return springsstretched between the two ends of the two pins. The rows of blades areoff-set alternately such that the cams at each end actuate only half theblades which therefore move in opposite directions.

Preferably, the blades are spring-loaded such that each tooth makes arelatively short gouged inscription and a retention hook on the brakeplate before retracting and disengaging from the brake plate.

The upper die plate may be spaced away from the centre die plate forpermitting removal and re-insertion of the tooling assembly (e.g. bysupport from smaller gas springs). The blade cartridge is preferablyconstructed for easy tooling change-over and maintenance. Preferably,the tooling assembly is mounted to the upper die plate on rails forpermitting removal and re-insertion of the tooling assembly. Preferably,at least one sensor is provided on or near the die set proximate to theanvil for monitoring the texturing operation of the tooling assembly(e.g. to monitor hook formation). Sensors may detect the height ofundersized burrs and/or ill-positioned plates and thereby provide inputto machine controls to stop the texturing process preventing inferiorplates from leaving the press.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 shows a perspective view of the die set with the base, centre andupper die plates, the cam blocks and blade cartridge, and the locationof the plate feed mechanism in dashed outline.

FIG. 2 shows the plate feed mechanism from the side in its forwardposition of plate delivery.

FIG. 3 shows the same as FIG. 2 in the rearward position for platepickup.

FIG. 4 shows the blade and insert tooth arrangement and an enlargementthereof.

FIG. 5 shows the prior art dies set in a press with the tooling securedto the ram face.

FIG. 6 shows the instant three plate die set in the same press with thetooling secured to the upper die plate.

FIG. 7 shows a simplified side view of the instant invention in itsresting state so as to clearly disclose the blade movement sequence.

FIG. 8 is an enlarged left portion of FIG. 7 where the upper die platecontacts the centre die plate.

FIG. 9 is the same as FIG. 8 but with the two die plates moving inunison.

DETAILED DESCRIPTION

Referring to the drawings, there are sometimes shown small gaps orspaces between components. This is for clarity of understanding but inactual fact most components fit tightly together except where otherwisenoted.

In FIG. 1 the instant three piece die set 100 has as its majorcomponents: upper die plate 200 with tooling assembly 400 and associatedcam blocks 300; centre die plate 500 with anvil 26; base or lower dieplate 600 with posts; and plate feed mechanism 700, shown as a placementoutline in FIG. 1 and in greater detail in FIGS. 2, 3. Die set 100installs in press 900 (FIG. 6) where it is attached to its bolster plateE. Press 800 and 900 have base F and upper frame B connected togetherwith tie rods C. Cylinder G has ram D that is reciprocated therein. Thepress 900 may be mechanical, hydraulic, or a servo type press.

The prior art show in block outline in FIG. 5 uses a two plate die setwith tooling attached to the press ram. This makes it difficult toinstall, adjust, test and change-out the tooling. Critically, thealignment of the tooling with the die set is also difficult given themass of the die set (many hundreds of pounds) and the need for itsprecise location beneath the separately mounted tooling. FIG. 6 showsthe same press with the three plate die set of the instant invention andhow the tooling alignment is pre-set prior to installing on the presswhere the die set location is not critical and therefore much easier andfaster.

Referring back to FIG. 1, base die plate 600 has base die plate 33 (withmeans to secure it to press bolster E), four rigid posts 30 secured instop blocks 35, two stepped riser blocks 36 with upper contact faces 36a. A removable slide 38 carries four manifolded gas springs 37 and islocated by two guides 31. On base die plate 33 is rigid block 34 withattachment means 32 to secure plate feed mechanism 700 thereto.

Upper die plate 200 has elastomeric pads 6 secured in recesses 5 in thetop surface of plate 1 as shown by arrow 7. These pads are compressed bythe descending ram D making for a cushioned, silent contact with top dieplate 1 and which also initiate the descent of upper plate 200. Fourthrough-bushings 4 slide on posts 30. Cam blocks 300 attach to theunderside and are separated by pressure plate 2 which has guides 3 toreceive tooling rails 18 on tooling assembly 400.

Referring to FIG. 1 and FIGS. 7-9 (where FIGS. 8, 9 show simplified lefthalf views of FIG. 7 for enlarged clarity) left and right cam blocks 300have secured body portions 8 with guided, spring-return moving elements.When die plate 200 descends each vertical moving element 9 contactssurface 36 a of riser block 36. Elements 9 have angular contact surfaces9 a. Each horizontal moving element 10 has a matching angular contactsurface 10 a. As die plate 200 descends, these angular surfaces engagein a sliding contact such that the horizontal moving elements 10 movetowards each other. Toothed blades 11, 14 held in tool assembly 400, arearranged to move under the force of horizontal moving elements 10.Horizontal blade motion is timed to begin just slightly before the teethcontact the brake plate A. In this way, the teeth skate (21 a in FIG. 8)into plate A to avoid unwanted sudden impact that would damage the sharptooth tips. After a certain distance of vertical descent of die plate200, shown change in gaps 67 and 67 a in FIGS. 8, 9, secured bodyportions 8 contact secured blocks 29 causing centre die plate 500 tothereafter descend with descending die plate 200. As descent of theupper and centre die plates continues, gap 66 between die plate 200 anddie plate 600 is reduced to gas 66 a, the descent being resisted by theadjustable force of gas springs 37 which allows teeth 21 to continueincising controllably across and into plate A, as indicated by buriedteeth 21 b in FIG. 9. Removable shims 68 in riser blocks 36 allowprecise adjustment to compensate for varying thicknesses of plate A andfor manufacturing/specification tolerances.

Centre die plate 500 has plate 22 with four post through-bushings 23 (toslide on posts 30) an anvil plate 26 on which brake plate A, isdelivered between guides 25 for texturing. Openings 24 enable steppedriser blocks 26 to protrude through plate 22 and to contact verticalmoving element 9 mounted in cam block 8. Centre die plate 500 also hasfour gas springs 27 of sufficient strength to hold upper die plate 200open over centre die plate 500 for rapid tooling change-out. Pressureblocks 29 have upper contact surfaces 28 that contact cam block contactsurfaces 9 a and transfer downward motion of upper die plate 200 tocentre die plate 500 such that both move downwards together compressingfirst gas springs 27 then gas springs 37. On the edge of plate 22 aretwo roller supports 29 on which rests and pivots the inboard end ofplate feed slides 44, 44 a.

Upper die plate 200 holds quick-change tooling assembly 400 whichincludes left blades 11 and right blades 14 having shorter and longerslots 20 formed in end portions. Blades 11 and 14 are arranged inalternating rows and are slidingly held between rigid side fences 13,15. The arrangement is such that the blades are offset horizontally andtheir respective teeth 21 are pointing in opposite directions. Springloaded left and right pins 16 engage the blades' slots and co-operatingslots in the side fences 15. Pins 16 are tensioned towards each othervia outboard springs 19. In this way blades 11, 14 are made to move inopposite directions so as to cancel out their inscribing forces makingit unnecessary to clamp brake plate A which speeds production. The sidefences 13, 15 are bolted 12 to a pressure plate 17 and the plain backsof the blades also contact plate 17. Pressure plate 17 has rails 18secured to its top surface that slidingly engage guide slots 3.

Attention is now drawn to FIGS. 2, 3 which show a side viewrepresentation of plate feed mechanism 600 at each end of itsoperational stroke. FIG. 2 shows the brake plate delivery position whileFIG. 3 shows the rearward brake pick up position. Main magazine member41 includes brake plate support rods 42 and is mounted rigidly to rigidblock 34 on base die plate 33. Brake plates A drop through an opening inmember 41 onto reciprocating slide 44 with sub-slide 44 a beneath. Bothslides pass freely through member 41 and are guided by same. Extendingfrom rigid block 34 are rigid support rods 51 along whose length slideblock 50 can be adjustably secured. Slide block 50 holds a separatehinge plate 50 a pivoted thereon via cross pin 45 and shown by arcedarrow lines 43. Slides 44, 44 a are secured to hinge plate 50 a. Alsoadjustably secured to rods 51 is a pneumatic cylinder 49 with mountingboss 48 and piston rod 47 which is secured to hinge block 50 such thatrod 47, slides 44 and 44 a, hinge block 50, and hinged plate 50 a, allreciprocate together along support rods 51. In this way, brake plates Adrop by gravity onto upper slide 44 and are moved one by one onto anvil26 by the reciprocating action of pneumatic cylinder 49 which is timedto the reciprocating movement of the press 900. Rollers 39 support theinboard ends of slides 44, 44 a and brake plates in conveyance, andallow free reciprocation left to right on anvil 26 as brake plates aresuccessively delivered thereon. Rollers 39 also move the slides up anddown as the center die plate so moves.

Slides 44, 44 a are made extra long which serves a very importantfunction, namely, it reduces the variation in delivery angle 46 of thebrake plate to the anvil 26 between guides 26 a. This means that thebrake plate can be delivered with only a small variation in height. Thisavoids a jamming condition frequently encountered in prior apparatuseswhich reciprocate the entire brake plate feed mechanism with the centredies plate. Attached to magazine member 41 are pawls 40, one of which isshown, which serve as one way controllers to prevent the rearwardmovement of brake plates resting on the slide 44 which necessarily musttravel rearwards.

Referring now to FIG. 4, blades 11, 14 have end slots 20 and cut-outs63. Cut-outs 63 receive inserts 61 such that enlarged or bulbousportions prevent the insert from falling from the blade. Certain insertshave cutting teeth 21. Certain inserts may also have no teeth (notshown). These are used as non-cutting spacers. All inserts have angledside portions 62. Cut-outs have matching angled sides 64 to provide aclose fit with the inserts. It is desirable to prevent relative motionbetween the inserts and their respective cut-outs which can lead totooth breakage and expensive production stops to correct. As can be seenin the magnified view in FIG. 4 there is provided a cut-out having aslightly deeper bulbous portion indicated by 65. Each insert 61 can thenbe driven by forces of operation 70 into a jammed tight conditionwhereby intimate contact between the walls of the insert and cut-outcannot be interfered with by their bulbous portions contacting first.

Although the invention has been shown and described with respect todetailed embodiments thereof, it should be understood by those skilledin the art that various changes in form and detail thereof may be madewithout departing from a broad purposive construction of the claimedinvention. For instance, although brake plates have been used as anexample throughout the foregoing disclosure, it will be appreciated thatthe methods and apparatus described herein may be equally applicable totexturing other workpieces.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A method for texturizing a workpiece using a die assembly installedwithin a press having a press ram, the method comprising: a) deliveringthe workpiece onto a centre die plate; b) forcing the press ram againstan upper die plate mounted above the centre die plate to descend a firstcontact surface associated with the upper die plate and a plurality ofblades mounted to the upper die plate toward the centre die plate; c)actuating horizontal movement of the blades; d) driving the blades downinto the workpiece; and e) contacting the first contact surface to asecond contact surface associated with the centre die plate to descendthe centre die plate in unison with the upper die plate.
 2. The methodof claim 1, wherein step (e) occurs after step (d).
 3. The method ofclaim 1, wherein step (d) occurs after step (c).
 4. The method of claim1 further comprising, prior to step (b), descending the press ram ontothe upper die plate.
 5. The method of claim 1 further comprising, afterstep (e), forcing horizontal movement of the blades across the workpieceto texturize the workpiece as the upper die plate and the centre dieplate descend in unison.
 6. The method of claim 5, wherein the bladesare vertically fixed relative to the workpiece as the upper die plateand the centre die plate descend in unison.